Clean power generation has become a major concern due to the effects of global warming. Renewable clean power generation has been developed using solar cells, wind turbines and wave turbines. However, an effective renewable power generation system has yet to be developed using ocean currents.
U.S. Pat. No. 4,383,182 discloses an apparatus for generating power from ocean currents. The apparatus is winged and is anchored to the ocean floor. A number of propellers are attached to the wing and are rotated by the ocean current. The rotation of the propellers causes rotation of a generator to generate electricity. The problem with this apparatus is that the apparatus is not easily moved to cater for changes in the direction of ocean currents. Further, the generation of energy is dependant upon the size and number of propellers to catch a specific area of current flow.
U.S. Pat. No. 4,163,904 discloses an underwater turbine plant for generating electrical power using ocean currents. The turbine is driven by the flow of the water current across the blades of the turbine. Again, the level of electricity generated is proportional to the area of water that the turbine plant is able to capture.
U.S. Pat. No. 4,335,319 discloses a hydroelectric power apparatus that includes a powerhouse containing a power generator above the powerhouse located above the surface of the water. A hydraulic turbine is lowered from the powerhouse when the ocean currents are sufficient to drive the turbine. The disadvantage with this apparatus is that power is required to extend and retract the turbine. Further, the ocean current area that is utilised is equivalent to the inlet area of the turbine.
U.S. Pat. No. 5,440,176 discloses a hydroelectric power plant similar to that of U.S. Pat. No. 4,335,319 in that a series of turbines are extended and retracted dependant upon the velocity of the ocean currents.
Similar disadvantages exist with the power plant disclosed in U.S. Pat. No. 5,440,176 as with the apparatus disclosed in U.S. Pat. No. 4,335,319.
U.S. Pat. No. 6,109,863 discloses a fully submersible apparatus for generating electricity. The apparatus includes a buoyant structure having a motor mounted thereto. A series of vanes are connected to the motor. The vanes are rotated by the ocean current to cause electricity to be generated. A disadvantage with this apparatus is that the generation of electricity is dependant upon the area of current that the vanes are able to capture.
U.S. Pat. No. 4,313,059 discloses a system for generating electricity from ocean currents. The system uses two drags that are connected to opposite ends of a cable. The middle of the cable is wrapped around a generator. The drags are lowered into the ocean and moved from a drag position to a non drag position to reciprocate movement of the cable. The disadvantage with this system is that the generator must be able to generate energy when rotated in both directions. Further, the energy supply is not constant as the generator is constantly changing directions.
GB Patent Application 2,214,239A discloses an apparatus for harnessing power from natural fluid flows. The apparatus includes a continuous belt having a number of vanes. The continuous belt encircles a pair of cylinders that are operatively connected to drive a generator. The continuous belt is orientated so that water flow across the vanes to drive the belt and hence rotate the cylinders. The problem with this apparatus is that water flows through a front set of vanes and then through a rear set of vanes on the continuous belt. This creates water turbulence in water that passes through the rear set of vanes and hence efficiency of the apparatus is reduced.